It is the purpose of this investigation to determine the extent of applicability of the polygenic model of inheritance to the analysis of malocclusion. Put into operational terms, this study is designed to determine whether different morphologic components of the skull are under equal polygenic control and whether these morphologic elements exhibit genotypic independence. Previous investigation of family data has supported the contention that craniofacial variation generally, and Class II div. 1 specifically, represent polygenic inheritance. The application and importance of these findings to diagnosis and treatment planning for the orthodontic patient has been demonstrated by the previous research supported by this grant. Further refinement of knowledge of the detailed inheritance in the craniofacial complex depends upon the utilization of an idealized study population. The Nubian population of Ballana, Egypt is uniquely suitable for the rigorous evaluation of the polygenic model of inheritance. The Nubian family data comprises a uniquely homogenous population of known origins, established family pedigrees, multiple marriages, first cousin marriage patterns, and stable culture and diet. The cephalometric, cast, dental record, and anthropometric data have already been collected and are housed in the Department of Orthodontics, School of Dentistry University of Michigan. Multivariate techniques of analysis will be used to assess the role of heredity in the development of the craniofacial complex.